Electrical control



Aug. 15, 1967 R R E 3,336,556

ELECTRICAL CONTROL Filed Dec. 1'7, 1964 INVENTOR FIG. 4-

POUL HENQKSEN BY A% DRNEY K United States Patent Ofiice 3,336,556 Patented Aug. 15, 1967 6,00 6 (Ilairns. ((l'l. 338-=-I%) An electric switch having a housing provided with a pair of spaced parallel walls containing pairs of notches having terminals mounted in at least two of the notches. An operating member slideably mounted within the housing shifts a spring provided with contact portions at the ends thereof from one position to another. The contact portions cooperate with the notches and the terminals therein for maintaining the operating member in a stable position. A pair of runners are provided on one of the surfaces of the operating member to facilitate movement of the operating member and a tongue on the operating member is slideably mounted in a groove in the housing enabling the operating member to move rectilinearly. When the switch housing is secured to a variable resistance control, rotary motion of a cam connected to a driver of the variable resistance control operably engages a cam follower secured to the operating member slideably moving the operating member and shifts the contact portions into and out of engagement with a pair of terminals.

The present invention relates to electrical controls, and, more particularly, to a combination variable resistance and switch control and to an electrical switch.

There are currently available on the market many different types of electrical switches attached to variable resistance controls. Some of the switches are of simple construction and are satisfactory for use in circuits operating at voltages below 120 to 150 volts. For obvious reasons, these switches cannot, however, be employed in circuits operating at higher voltages. It would therefore be desirable to provide an electrical switch of exceptionally simple and inexpensive design functioning with perfect effectiveness, both with regard to efficient contact making and provision of the necessary creep distances, spark extinguishing, and the like resulting in a compact construction making the outer dimensions of the switch extremely small and adaptable for use with a variable resistance control of the rotatable type. Moreover, by employing a novel cam action, the rotary motion of the variable resistance control slideably shifts an operating member of the electric switch for making and breaking the contacts of the switch.

Accordingly, it is an object of the present invention to provide an electrical switch having a minimum number of parts and of such simple and facile construction that its efiiciency will never be affected by wear.

7 Another object of the present invention is provide 'an electrical switch employing a resilient spring having contact portions on the ends thereof functioning as a current conducting member as well as a part of a detent mechanism.

An additional object of the present invention is to provide an electrical switch having a pair of electrically nonconductive parallel walls provided with notches and movable contact portions adapted to cooperate with the notches for positioning the operating member of the switch in an engaged or disengaged position.

A further object of the present invention is to provide an electrical switch fixedly secured to a variable resistance control wherein the driver of the variable resistance control is provided with a cam for engaging and slideably shifting the operating member of the switch.

Further objects and advantages of the present invention will become apparent as the following description proceeds, and the features of novelty characterizing the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

Briefly, the present invention is concerned with an electrical switch comprising a helical spring having at both ends smoothly rounded contact portions interconnected electrically and cooperating with at least two pairs of notches in opposed, parallel walls of a rigid insulating member, e.g., a casing, at least one of the said pairs of notches having electric contacts at the bottom thereof. An operating member slideably mounted between the parallel Walls is provided with an elongated slot for engagement with the spring. The electrical connection between the contact portions may be provided by means of a soft wire or other suitable means and the spring may be made of any suitable material, but according to a preferred form of the invention, the electrical connection between the contact pieces is obtained solely by means of the coiled helical spring of an electrically conductive spring material and no other connection is required. In a preferred form of the invention, the operating member and the rigid insulating member are provided with guide means extending in the moving direction of the operating member. The switch is combined with a variable resistance control and the combination is increased due to the improvement resulting from the decrease of the number of parts.

For a better understanding of the present invention, reference may be had to the accompanying drawings wherein the same reference numerals have been applied to like parts and wherein:

FIGURE 1a is an isometric view of a combination variable resistance control having secured thereto an electrical switch built in accord with the present invention;

FIGURE 1b is a fragmentary isometric view of the electrical switch shown in FIGURE la of the drawings;

FIGURE 2 is a sectional view of the control of FIG- URE 1a showing the top of the switch;

FIGURE 3 is a sectional view similar to FIGURE 2 with the cover of the switch removed;

FIGURE 4 is a sectional view taken along line IV-IV of FIGURE 3, assuming that the cover is assembled to the casing of the switch; and

FIGURE 5 is a sectional view taken along line V-V of the switch shown in FIGURE 3, assuming that the cover is assembled to the casing of the switch.

Referring now to FIGURE 1a of the drawings, there is illustrated a combination electrical control, generally indicated at 10, comprising a variable resistance control 11 and an electrical switch 12 secured to the control 11.

Considering first the variable resistance control 11, it comprises an arcuate resistance element 13 carried by an apertured base 14. Suitable terminals 15 are connected to the ends of the resistance element 13 and a contactor 16 constrained to rotate with a driver 17 is in wiping contact with the resistance element 13 intermediate the ends thereof. A shaft 18 rotatably journaled in the aperture in the base is integrally connected to the driver 17 and a cup-shaped housing 19 secured to the base 14 by tabs or other suitable means encloses the driver and the resistance element 13.

The electrical switch comprises a casing 21 of electrically nonconductive material having opposed parallel walls 22 and 23 provided with notches 24 and 25 preferably of U or V shape. A portion of a terminal 26 having a contact 27 is fixedly secured in the bottom of each of the notches 24 and recessed portions 28 and 29 are provided in the parallel walls 22 and 23 for receiving the terminals to assure that a cover 30 interposed between the casing 21 of the electrical switch 12 and the housing 19 does not interfere with the securing of the terminals 26 to the walls 22 and 23. For the purpose of securing the electrical switch 12 to the variable resistance control 11, the housing 19 is provided with a pair of depending bifurcated tabs 31 disposed in suitable slots 32 provided in the easing 21.

As best shown in FIGURE 3 of the drawings, the notches 24 and 25 in the wall 22 face the notches 24 and 25 in the other wall 23 forming two pair of notches 24 with the contacts 27 and two pairs of notches 25 without contacts. Each pair of notches 24 with the contacts 27 arranged therein is interconnected by means of a coiled helical spring 33 provided with contact portions 34. It is to be understood that each pair of notches 24 with the contacts arranged therein forms a switching means for one side of a circuit and, whenever only one side of a circuit need be opened, the electrical switch may consist of only one spring 33. On the other hand, not shown terminals can be fixedly secured in the notches 25 for providing a changeover between different circuits. In the embodiment shown in the drawings, both sides of the circuit are opened.

For the purpose of slideably shifting the springs 33 from the notches 24 to the notches 25, the springs are disposed in elongated slots 35 provided in an operating member 36 and constrained to move with the operating member 36 as it is shifted between the parallel walls 22 and 23. Guide means, e.g., an elongated groove 37, is provided in the bottom 21a of the casing 21 and a tongue 38 carried by the operating member is disposed in the groove 37 for controlling movement of the operating member in the proper direction. To facilitate movement of the operating member from a first position to a second position, a pair of depending runners 39 integral with the operating member 36 slideably engage the bottom 21a of the casing 21 and similar runners 40 slideably engage the cover 30.

Preferably and as shown in the drawings, an upended cam follower 41 integral with the operating member 36 extends through an opening 30a in the cover 30 and is engaged by a cam 42 integral with the driver. The cam 42 depends from the bottom surface of the driver and, as the driver, when viewed from the shaft end, is rotated in a counterclockwise direction, the cam approaches the cam follower 41 from the left side of FIGURE 2. Further rotation of the driver engages the cam 42 with the cam follower 41 and displaces the operating member 36 from the position shown in FIGURE 3 of the drawings in the direction indicated by the arrow 43 shifting the springs 33 and the contact portions 34 from the notches 24 to the notches 25, i.e., the cam follow 41 is shifted from the left to the right side of the opening 30a by the cam 42. Reverse rotation of the driver shifts the cam follower 41 back to the left side of the opening 30a. The compression of the springs 33 and the cooperation of the contact portions 34 with the notches 24 produces a movement rapidly snapping the contact portions 34 into notches 25 and quickly opening or changing the circuit.

The operation of the present invention will be readily understood in view of the detailed description included above, and no further discussion is included herewith. It will be appreciated that by employing suitable means for fixedly securing the cover to the casing of the electrical switch, the switch can be operated independently of the variable resistance control.

While there has been illustrated and described what is at present considered to be a preferred embodiment of the present invention, it will be appreciated that numerous changes and modifications are likely to occur to those skilled in the art, and it is intended in the appended claims to cover all those changes and modifications which fall within the true spirit and scope of the present invention.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. An electrical switch comprising a pair of opposed electrically nonconductive parallel walls, a pair of notches disposed in the walls, the parallel wallsv being provided with cutout portions communicating with the. notches, a terminal disposed in each of the notches and the cutout portions, a spring provided with contact portions at the ends thereof cooperating with the terminals in the notches, an operating member slideably mounted between the parallel walls, the contact portions cooperating with the notches and the terminals therein for maintaining the operating member in a stable position, and means carried by the operating member for shifting the contact portions into and out of the notches.

2. An electrical switch comprising a casing having a pair of opposed electrically nonconductive parallel walls, four pairs of notches disposed in the walls, terminals disposed in at least two of the pairs of notches, a pair of springs provided with contact portions at the ends thereof cooperating with the notches, an operating member slideably mounted between the parallel walls, the contact portions cooperating with the notches and the terminals therein for maintaining the operating member in a stable position, a pair of runners disposedat least on one of the surfaces of the operating member in the moving direction of the operating member for facilitating movement of the operating member, the springs being contained in a pair of elongated slots provided in the member.

3. The switch of claim 2 wherein a groove is provided in the bottom of the casing, and a tongue integral with the operating member is slideably mounted in the groove.

4. In a variable resistance and electrical switch control, the combination of a base, means defining a resistance path carried by the base, driver means in wiping contact with the resistance path, a casing having a pair of opposed electrically nonconductive parallel walls connected to the base, a pair of notches disposed in the walls, a terminal in one of the notches of each of the walls, a spring provided with contact portions at the ends thereof cooperating with the notches, an operating member slideably mounted between the parallel walls, a cam integral with the driver means engageable with the operating member, and means carried by'the operating member for shifting each of the contact portions into and out of engagement with the terminals as the operating member is slideably shifted upon rotation of the driver means.

5. An electrical control comprising a housing, a base secured to the housing, a resistance element supported on the base, a driver rotatably mounted in the housing, a contactor constrained to rotate with the driver in wiping contact with the resistance element, a casing fixedly secured to the housing and provided with a pair of opposed electrically nonconductive parallel walls, a first pair and a second pair of notches disposed in the walls, a terminal having a stationary contact mounted in each of the notches of the first pair, a coiled helical spring provided with contact portions at the ends thereof cooperating with the notches of the first pair, an electrically non-conductive operating member slideably mounted between the parallel walls, and a lost motion connection between the driver and the operating member for shifting the operating member from a first position to a second position and for shifting the contact portions from the notches of the first pair to the notches of the second pair.

6. In an electrical control, the combination of a resistance element, a driver rotatably mounted with respect to the resistance element, a contact carried by the driver in wiping contact with the resistance element, a pair of opposed electrically nonconductive parallel walls in fixed 5 6 relationship to the resistance element, a pair of notches References Cited disposed in the walls, a terminal having a stationary con- UNITED STATES PATENTS tact mounted in each of the notches, a spring provided With contact portions at the ends thereof cooperating with 1696902 1/1929 claim the stationary contacts, an operating member slideably 5 2488'670 11/1949 Koenig 200.16 mounted between the parallel Walls, a lost motion con- 215211561 9/1950 Batchener 200.16 nection between the driver and the operating member for 23 32:;

slideably shifting the operating member from a first position to a second position upon rotation of the driver, and means carried by the operating member for shifting the RICHARD WOOD Prlma'y Emmmer' contact portions of the spring into and out of the notches. J. G. SMITH, Assistant Examiner. 

2. AN ELECTRICAL SWITCH COMPRISING A CASING HAVING A PAIR OF OPPOSED ELECTRICALLY NONCONDUCTIVE PARALLEL WALLS, FOUR PAIRS OF NOTCHES DISPOSED IN THE WALLS, TERMINALS DISPOSED IN AT LEAST TWO OF THE PAIRS OF NOTCHES, A PAIR OF SPRINGS PROVIDED WITH CONTACT PORTIONS AT THE ENDS THEREOF COOPERATING WITH THE NOTCHES, AN OPERATING MEMBER SLIDEABLY MOUNTED BETWEEN THE PARALLEL WALLS, THE CONTACT PORTIONS COOPERATING WITH THE NOTCHES AND THE TERMINALS THEREIN FOR MAINTAINING THE OPERATING MEMBER IN A STABLE POSITION, A PAIR OF RUNNERS DISPOSED AT LEAST ON ONE OF THE SURFACES OF THE OPERATING MEMBER IN THE MOVING DIRECTION OF THE OPERATING MEMBER FOR FACILITATING MOVEMENT OF THE OPERATING MEMBER, THE SPRINGS BEING CONTAINED IN A PAIR OF ELONGATED SLOTS PROVIDED IN THE MEMBER. 